Zoom lens assembly

ABSTRACT

A zoom lens assembly for a miniature camera, such as those used in cellular telephones and other personal electronic devices, is disclosed. One or more lenses of the zoom lens assembly are moved in and/or out of the optical path of the zoom lens assembly to change the magnification of the lens. Since the magnification does not necessarily require movement of lenses along the optical path of the camera, the length of the zoom lens assembly, and consequently of the camera as well, is substantially reduced.

PRIORITY CLAIM

This patent application claims the benefit of the priority date of U.S.provisional patent application Ser. No. 60/657,261, filed on Feb. 28,2005 and entitled AUTOFOCUS CAMERA (docket no. M-15826-V1 US) pursuantto 35 USC 119. The entire contents of this provisional patentapplication are hereby expressly incorporated by reference.

TECHNICAL FIELD

The present invention relates generally to optics. The present inventionrelates more particularly to a zoom lens assembly having a reducedlength such that it is suitable for use in miniature cameras.

BACKGROUND

Miniature cameras are well known. Miniature cameras are widely used incontemporary cellular telephones. They are also used in other devices,such as laptop computers and personal digital assistants (PDAs).Miniature cameras can even be used as stand alone devices for suchapplications as security and surveillance.

Contemporary miniature cameras, such as those used in cellulartelephones, do not typically have zoom lenses. Zoom lenses necessitatethe use of one or more additional lens elements that inherently increasethe length of the camera (at least according to contemporary practice).As those skilled in the art will appreciate, miniature cameras forcellular telephones and the like are subject to strict size constraints.These size constrains limit the overall length of the camera and thuseither prohibit the use of zoom lenses or substantially mitigate theeffectiveness thereof by limiting the number of lens elements and/or therange of motion thereof.

However, zoom lenses are desirable. Zoom lenses provide magnificationthat enhances the detail of images, such as those taken from a distance.As such, it is desirable to have a zoom lens in the camera of a cellulartelephone or the like. Moreover, it is desirable to provide a zoom lensthat is short enough in length to be used in miniature cameras, such asthose cameras that are used in cellular telephones and the like.

BRIEF SUMMARY

Systems and methods are disclosed herein to provide for the zooming of aminiature camera. More particularly, a zoom lens assembly for miniaturecameras, such as those used in cellular telephones and other personalelectronic devices, is disclosed. One or more lenses of the zoom lensassembly can be moved in and/or out of the optical path of the zoom lensassembly to change the magnification of the lens. For example, aplurality of lenses can be configured to move in and out of the opticalpath.

Lens parameters other than magnification can similarly be changed,either while at the same time changing magnification or while leavingmagnification unchanged. For example, various aberrations can becorrected by adding and/or removing one or more lenses, wherein suchremoving or adding of lens can optionally also change magnification.

Embodiments of the present invention can effectively simulate themovement of a lens, exchange one lens for another, and simulate themovement of a lens while exchanging it for another lens. Movement can besimulated so as to change the optical properties of a system, such as tovary magnification or zoom.

One lens can be exchanged for another so as to vary the opticalproperties of the lens (and consequently of the optical system, aswell). For example, a lens can be exchanged with another that hasdifferent aberration corrections qualities.

Optical elements other than lenses can be placed into and removed fromthe optical path. Thus, both refractive and diffractive elements can beselectively placed into and removed from the optical path. Indeed, otheroptical elements such as spectral filters and polarization filters cansimilarly be added to or removed from the optical path.

More particularly, a plurality of lenses wherein each lens hasapproximately the same power can be configured to move in and out of theoptical path. Alternatively, a plurality of lenses wherein each lens hasa different power can be configured to move in and out of the opticalpath.

Optionally, at least one lens can configured to move along (rather thanin and out of) the optical path of the zoom lens assembly. For example,at least one of the lenses that is configured to move in and out of theoptical path can also be configured to move along the optical path. As afurther example, all of the lenses that are configured to move in andout of the optical path can also be configured to move along the opticalpath.

All of the lenses that are configured to move in and out of the opticalpath can also be configured to move along the optical path in unisonwith respect to one another. Alternatively, movement of the lenses alongthe optical path can be individually controllable. Thus, the lenses donot have to move along the optical path in unison with respect to oneanother.

Rather than configuring one or more of the lenses that move in and outof the optical path such that they can also move along the optical path,one or more other lenses (that is, lenses that are not configured tomove in and out of the optical path), can be configured to move alongthe optical path. In any case, lenses that are configured to move alongthe optical path of the zoom lens assembly can be made to do so in orderto provide fine adjustment of the magnification or other opticalparameter provided by the zoom lens assembly.

Optionally, the lens(es) can be configured to move in and out of theoptical path of the zoom lens assembly at a rate that is faster than aframe rate of the camera. For example, the lens(es) can be configured tomove in and out of the optical path of the zoom lens assembly at a ratethat is faster than 30 times per second. In this manner, a lens can bemoved into or out of the optical path of the zoom lens assembly betweenframes, such that the movement of the lens does not adversely affectimaging.

According to another aspect, the present invention comprises a shutterblade for a camera, wherein the shutter blade comprises a light blockingportion that is configured to block light from entering the camera andat least one lens that is configured to magnify an image of the camera.The shutter can contain a plurality of lenses that are configured tomagnify an image of the camera, such that a corresponding plurality ofdifferent magnifications can be provided for the image.

Since varying the magnification does not necessarily require movement oflenses along the optical path of the camera (as is required incontemporary zoom lens assemblies), the length of the zoom lensassembly, and consequently the length of the camera as well, can besubstantially reduced. As such, a camera having smaller overalldimensions can be made. Such a camera is suitable for use in cellulartelephones and other personal electronic devices.

This invention will be more fully understood in conjunction with thefollowing detailed description taken together with the followingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a semi-schematic side view of a camera having a zoom lensassembly according to an exemplary embodiment of the present invention,wherein all of the lenses thereof are configured to move in and out ofthe optical path of the zoom lens assembly and all of the lenses areshown positioned out of the optical path;

FIG. 2 is a semi-schematic side view of the camera having a zoom lensassembly of FIG. 1, wherein the first, third, and fourth lenses arepositioned in the optical path of the zoom lens assembly and the secondlens is not positioned in the optical path of the zoom lens assembly;

FIG. 3 is a semi-schematic front view of a shutter blade having a zoomlens according to an exemplary embodiment of the present invention;

FIG. 4 is a semi-schematic front view of a shutter blade having aplurality of zoom lenses according to an exemplary embodiment of thepresent invention;

FIG. 5 is a semi-schematic side view of a camera having a zoom lensassembly according to an exemplary embodiment of the present invention,wherein all of the lenses are configured to move in and out of theoptical path of the zoom lens assembly and at least one of the lenses isalso configured to move along the optical path and wherein all of thelenses are shown out of the optical path;

FIG. 6 is a semi-schematic side view of a camera having a zoom lensassembly according to an exemplary embodiment of the present invention,wherein all but one of the lenses are configured to move in and out ofthe optical path of the zoom lens assembly and only the lens that is notconfigured to move in and out of the optical path is configured to movealong the optical path;

FIG. 7 is a semi-schematic side view of a camera having a zoom lensassembly according to an exemplary embodiment of the present invention,wherein a plurality (in this instance, two) of lenses are configured tomove in and out of each position along the optical path of the zoom lensassembly and all of the lenses are shown positioned out of the opticalpath; and

FIG. 8 is a front view of a cellular telephone having a zoom camera,according to an embodiment of the present invention.

Embodiments of the present invention and their advantages are bestunderstood by referring to the detailed description that follows. Itshould be appreciated that like reference numerals are used to identifylike elements illustrated in one or more of the figures.

DETAILED DESCRIPTION OF THE INVENTION

A method and system for providing zoom for a miniature camera aredisclosed. According to this method, one or more lenses can be movedinto and out of the optical path of a zoom lens assembly. This can bedone either instead of moving the lenses along the optical path of thezoom lens assembly or in addition thereto. In either instanced, the needto move lenses along the optical path of the camera is mitigated,consequently facilitating a reduction in the length of the optical pathand thus a corresponding reduction in the length of the camera.

Movement along the optical path can be defined herein as movement towardor away from an imager (at least for collinear optical systems such asthose shown in FIGS. 1, 2, 5, and 6). Movement into and out of theoptical path can be movement that is generally perpendicular to theoptical path.

Referring now to FIG. 1, according to one embodiment of the presentinvention, a camera is defined by a zoom lens assembly 10, a focusinglens assembly 11, and an imaging sensor 12. Lenses 14-17 of zoom lensassembly 10 can be moved in and out of an optical path 13 of the cameraso as to change a magnification and/or other aspect of an image formedupon imaging sensor 12, as discussed in detail below. Focusing lensassembly 11 can be moved along optical path 13 so as to effect focusing,according to well known principles.

Any desired ones of lens 14-17 can be moved from the positions shown inFIG. 1 (which are out of optical path 13) to positions that are inoptical path 13. Thus, any desired combination of lenses 14-17 candefine the magnification and/or other optical quality of the imageformed upon imaging sensor 12.

Referring now to FIG. 2, one example of a combination of lenses 14-17that can be moved from a position out of optical path 13 to a positionin optical path 13 is shown. According to this example, first lens 14,third lens 16, and fourth lens 17 have been moved into optical path 13.In this manner, a plurality of different combinations of lenses can bemoved into optical path 13 so as to provide a corresponding plurality ofdifferent magnifications and/or other qualities of an image upon imagingsensor 12.

It is important to appreciate that FIG. 2 is just one example of acombination of lenses 14-17 that can be moved from a position out ofoptical path 13 to a position in optical path 13. For example, anysingle lens 14-17 could be so moved, any pair of lenses 14-17 could beso moved, any three lenses 14-17 could be so moved, and all of lenses14-17 could be so moved.

Lenses 14-17 can all have substantially identical powers and otherqualities (such as aberration correction). In this instance, moving asingle lens 14-17 out of optical path 13 and then moving another singlelens 14-17 into optical path 13 is somewhat equivalent to moving a lensalong optical path 13 by the distance separating the two lenses. Forexample, moving first lens 14 out of optical path 13 (after it has firstbeen moved thereinto) and then moving second lens 15 into optical path13 is somewhat equivalent to moving a single lens having the same powerand aberration corrections as first lens 14 from the position of firstlens 14 in optical path 13 to the position of second lens 15 in opticalpath 13. Thus, we have the ability to effectively move a lens. That is,the effect of such swapping of lenses 14 and 15 is similar to the effectof moving lens 14.

Moving two lenses 14-17 into the optical path 13 changes the totalmagnification power as compared to moving a single lens 14-17 into theoptical path. Adding a lens can either increase or decrease the totalmagnification. Similarly, removing a lens can either increase ordecrease the total magnification.

Additionally, we have the ability to change the lens (such as toeffectively change the power or other quality thereof), either as wemove the lens or as we leave it stationary. Thus, swapping of two lensescan change qualities of the lens such as magnification and/or aberrationcorrection, either with or without effectively changing the positionthereof.

Effectively moving a lens, such as by moving a lens 14-17 out of theoptical path and subsequently moving a different, but substantiallyidentical lens 14-17, into the optical path, can change themagnification. Thus, the effect of a contemporary zoom lens (wherein oneor more lenses move along the optical path) can be simulated.

Lenses 14-17 can have different powers with respect to one another. Inthis instance, replacing any one lens with another lens is not merelyequivalent to moving the first lens. Replacing one lens with another caninstead be equivalent to removing one lens and replacing it with adifferent lens at a different position.

The power of lenses 14-17 can all be the same or can differ in anydesire manner. Thus, the power of lenses 14-17 can increase by afractional amount, such as by 10%, from one lens to the next.Alternatively, the power of lenses 14-17 can double, or increase by adecade, from front to back, from back to front, or in any other desiredmanner.

Since any desired one of lenses 14-17 or any desired combination oflenses 14-17 can be moved into optical path 13, a wide range ofmagnifications or other parameters can be provided. This is particularlytrue if the power of each of lenses 14-17 differs. The more that thepower or other attribute of each of lenses 14-17 differs with respect toone another, the wider the range can be.

One or more of lenses 14-17 can be configured for close focusing. Forexample, one or more of lenses 14-17 can define a macro configuration,such as for focusing a few centimeters from first lens 14.

The discussion and showing of four lenses 14-17 of zoom lens assembly 10is by way of illustration only and not by way of limitation. Any desirednumber of such lenses can be used. This, zoom lens assembly 10 can beconfigured so as to move one, two, three, four, five, six, or morelenses into and out of optical path 13 of the camera.

Referring now to FIG. 3, a shutter blade 30 can be configured to place azoom lens, macro lens, or other lens in the optical path of a camera.Thus, shutter blade 30 can comprise a solid or light blocking portion 32which obscures the optical path until an exposure is desired. Shutterblade 30 can comprise an opening 33 that facilitates an exposure whenplaced in the optical path. Opening 33 can have no lens at all, or cancontain a lens that has no magnification (but can optionally provideaberration correction). Alternatively, shutter blade 30 can beconfigured to move so as to be entirely out of the optical path when anexposure is desired. Further, shutter blade 30 can place lens 34 in theoptical path when an exposure is desired. Thus, shutter blade 30 canhave three positions, i.e., a first position that blocks light, a secondposition that can let light enter without magnification, and a thirdposition that provides magnification or zoom. A pivot 31 facilitatesmovement of shutter 30 according to well known principles.

Referring now to FIG. 4, a shutter blade 40 can comprise a plurality oflenses 44 and 45. Lenses 44 and 45 can be different with respect to oneanother, so as to provide different amounts of magnification ordifferent aberration corrections, for example. One or more of lenses 43and 45 can be a macro lens. Opening 43 can contain no lens at all, or alens with no magnification. A pivot 41 facilitates movement of shutter40 according to well known principles. Thus, shutter blade 40 can havefour or more positions, i.e., a first position that blocks light, asecond position that can let light enter without magnification, and atleast two additional positions that provide magnification and/oraberration correction.

Shutter blades 30, 40 of FIGS. 3 and 4 can be used either with orwithout a zoom lens assembly as shown in FIG. 1. Indeed, shutter bladeslike those of FIGS. 3 and 4 can be used to move lenses into and out ofoptical path 13 according to the embodiment shown in FIG. 1. In thismanner, more than one lens is available to move into the optical path 13at the positions of each of lenses 14-17. An example of a zoom lensassembly where more than one lens can move into each position of theoptical path is shown in FIG. 7 and a shutter blade such as that of FIG.3 or FIG. 4 can be used to effect such operation.

Optical elements other than lenses can be used in the shutter blades ofFIGS. 3 and 4. For example, spectral filters, polarizing filters, or anyother optical elements can be used. Each position of the shutter bladecan have more than one optical element, such as a lens and a filter.Thus, each position of the shutter blade can have any desiredcombination of optical elements.

Referring now to FIG. 5, lenses 14-17 of the zoom lens assembly can beconfigured so as to move along optical path 13. In this manner, any oflenses 14-17 that are in optical path 13 can be moved along optical path13 so as to fine tune the magnification provided thereby. Thus, if oneof the discrete magnifications, for example, provided by a particularcombination of lenses 14-17 being in optical path 13 is not a desiredmagnification, then all of lenses 14-17 that are in optical path 13 canbe moved either toward or away from imaging sensor 12 so as to providethe desired magnification.

Referring now to FIG. 6, only lens 17 is movable along optical path 13.Lens 17 can be permanently in optical path 13. Thus, lens 17 can bededicated to movement along optical path 13, while lenses 14-16 arededicated to movement in and out of optical path 13.

Any desired number of lenses can be configured so as to move in anydesired fashion, according to the present invention. Thus, any of lenses14-17 can be configured to move in and out of optical path 13 and any oflenses 14-17 can be configured to move along optical path 13. By movinglenses 14-17 into or out of optical path 13, larger changes inmagnification can be obtained. By moving any of lenses 14-17 that are inoptical path 13 along optical path 13, smaller changes in magnificationcan be obtained.

The amount of movement of lenses 14-17 along optical path 13 can be muchsmaller that the movement of the lenses of a contemporary zoom lensassembly along the optical path thereof. Thus, the size of a zoom lensassembly that is configured for such movement along optical axis 13 canbe substantially smaller that a contemporary zoom lens assembly.

Referring now to FIG. 7, a plurality of lenses can be configured to moveinto each position along the light path of the zoom lens assembly 10.That is, rather than only being able to move a single lens 14-17 into agiven position (as is the case for the zoom lens assemblies of FIGS. 1,2, 5, and 6), any one of a plurality of lenses can be moved into a givenposition. More particularly, as shown in FIG. 7, either of two lensescan be moved into each position along the light path of zoom lensassembly 10. Thus, more flexibility in the possible magnification and/oraberration corrections is possible.

For example, either lens 14 or lens 71 can be moved into the leftmost orfirst position, either lens 15 or lens 72 can be moved into the secondposition, either lens 16 or lens 73 can be moved into the thirdposition, and either lens 17 or lens 74 can be moved into the last orfourth position. Of course, no lens at all needs to be moved into anyposition, if desired. Thus, any given position can have no lens or alens selected from the plurality of lenses that can move into thatposition.

Moving lenses in and out of the optical path of the camera can be doneso as to simulate or achieve the effect of lens movement (so as to varymagnification, for example). It can also be done so as to change someaspect of the lens, such as the aberration correction that the lensprovides, without achieving the effect of lens movement. It can also bedone so as to both achieve the effect of lens movement and to changesome aspect of the lens. Thus, such swapping of lenses can be done so asto change lenses or so as to effectively move lenses. When one lenses isswapped for another, the other lens can be identical, can have one ormore different surface curvatures, can have different elements or adifferent number of elements, and/or can have one or more elements withdifferent indices of refractions.

Lenses 14-17 and 71-74 can be moved in and out of the optical path byany suitable method or device. For example, lenses 14-17 and 71-74 canbe moved in and out of the optical by using an actuator or motor, suchas a Lorentz actuator. Micro electromechanical systems (MEMS) can beused to move lenses 14-17 and 71-74 in and out of the optical path.

Referring now to FIG. 8, a cellular telephone 80 comprises a cellulartransceiver 81 and a camera 82. Camera 82 can comprise a zoom lensassembly according to one or more embodiments of the present invention.For example, camera 82 can comprise the zoom lens assembly of FIG. 1,FIG. 5, FIG. 6, or FIG. 7 and/or the shutter blade of FIG. 3 or FIG. 4.

Although discussed herein as being suitable for use in miniaturecameras, one or more aspects of the present invention may be similarlysuitable for use in non-miniature cameras.

Lenses are described herein as the optical elements that are moved inand out of the optical path so as to achieve desired optical effects,e.g., magnification or zoom. However, other types of optical elementsmay similarly be moved in and out of the optical path to achieve avariety of different desired optical effects. For example, spectralfilters, polarizing filters, diffraction gratings, or any other desiredoptical elements may be moved in and out of the optical path accordingto the present invention. Thus, discussion of lenses herein is by way ofexample only and not by way of limitation.

Further, although one or more embodiments of the present invention arediscussed as being either zoom lens assemblies or for use in zoom lensassemblies, those skilled in the art will appreciate that applicationsof the present invention need not be limited to zoom lens assemblies oruse therein. For example, lenses can be moved in and out of an opticalpath to effect focusing, zoom, the use of filters, or for any otherdesired reason.

By eliminating or mitigating movement of zoom lens elements along theoptical axis of a camera, the length of the camera can be substantiallyreduced. Thus, a camera having zoom capabilities that is suitable foruse in personal electronic devices such as cellular telephones can bemade.

Embodiments described above illustrate, but do not limit, the invention.It should also be understood that numerous modifications and variationsare possible in accordance with the principles of the present invention.Accordingly, the scope of the invention is defined only by the followingclaims.

1. A zoom lens assembly comprising at least one optical elementconfigured to move in and out of an optical path of the zoom lensassembly.
 2. The zoom lens assembly as recited in claim 1, wherein atleast one optical element comprises a plurality of lenses that areconfigured to move in and out of the optical path.
 3. The zoom lensassembly as recited in claim 1, wherein at least one optical elementcomprises a plurality of lenses that are configured to move in and outof the optical path and wherein each lens has approximately the samepower.
 4. The zoom lens assembly as recited in claim 1, wherein at leastone optical element comprises a plurality of lenses that are configuredto move in and out of the optical path and wherein each lens has asubstantially different power.
 5. The zoom lens assembly as recited inclaim 1, further comprising at least one lens that is configured to movealong the optical path thereof.
 6. The zoom lens assembly as recited inclaim 1, wherein at least one of the optical elements that is configuredto move in and out of the optical path is also configured to move alongthe optical path.
 7. The zoom lens assembly as recited in claim 1,wherein all of the optical elements that are configured to move in andout of the optical path are also configured to move along the opticalpath.
 8. The zoom lens assembly as recited in claim 1, wherein all ofthe optical elements that are configured to move in and out of theoptical path are also configured to move along the optical path inunison.
 9. The zoom lens assembly as recited in claim 1, wherein all ofthe optical elements that are configured to move in and out of theoptical path are also configured to move along the optical path andmovement of the optical elements along the optical path is individuallycontrollable.
 10. The zoom lens assembly as recited in claim 1, whereinthe optical element(s) are configured to move in and out of an opticalpath of the zoom lens assembly at a rate faster than a frame rate of thecamera.
 11. The zoom lens assembly as recited in claim 1, wherein theoptical element(s) are configured to move in and out of an optical pathof the zoom lens assembly at a rate faster than 30 times per second. 12.The zoom lens assembly as recited in claim 1, wherein the opticalelement(s) comprise at least one of a lens, a spectral filter, apolarization filter, and a diffraction grating.
 13. A camera comprising:a focusing lens assembly; an image sensor upon which an image is focusedby the focusing lens; and a zoom lens assembly comprising at least onelens configured to move in and out of an optical path of the zoom lensassembly.
 14. The camera as recited in claim 13, wherein at least onelens comprises a plurality of lenses that are configured to move in andout of the optical path and wherein each lens has approximately the samepower.
 15. The camera as recited in claim 13, wherein at least one lenscomprises a plurality of lenses that are configured to move in and outof the optical path and wherein each lens has a substantially differentpower.
 16. The camera as recited in claim 13, further comprising atleast one lens that is configured to move along the optical paththereof.
 17. A camera comprising: a focusing lens assembly; an imagesensor upon which an image is focused by the focusing lens; and meansfor changing a magnification of an image by moving at least one lens inand out of an optical path of the zoom lens assembly.
 18. A cellulartelephone comprising: a telephone transceiver; and a camera, the cameracomprising a zoom lens assembly comprising at least one lens configuredto move in and out of an optical path of the zoom lens assembly.
 19. Ashutter blade for a camera, the shutter blade comprising: a lightblocking portion of the shutter blade that is configured to block lightfrom entering the camera; and at least one lens attached to the shutterblade that is configured to magnify an image.
 20. A zoom lens/shutterassembly for a camera, the zoom lens/shutter assembly comprising: ashutter blade; a light blocking portion of the shutter blade that isconfigured to block light from entering the camera; at least one lensattached to the shutter blade, the lens being configured to magnify animage of the camera.
 21. The zoom lens/shutter assembly as recited inclaim 20, wherein at least one lens comprises a plurality of lenses thatare configured to magnify an image of the camera, each lens beingconfigured to magnify the image by a different amount and each lensbeing individually selectable for placement into a light path of thecamera.
 22. A method for zooming a camera, the method comprising movinga lens into an optical path of the camera.
 23. The method as recited inclaim 22, wherein moving a lens into an optical path of the cameracomprising moving a shutter blade having the lens attached thereto. 24.A method for achieving an effect similar to that of moving a lens in acamera, the method comprising moving a first lens out of a firstposition in an optical path of the camera and moving a second lens intoa second position of the optical path of the camera, wherein the secondlens is substantially identical to the first lens and wherein the firstand second positions are different from one another.
 25. A method forchanging a parameter associated with a lens of a miniature camera, themethod comprising moving a first lens out of an optical path of thecamera and moving a second lens into the optical path of the camera atthe same position where the first lens was, wherein the second lens hasa different value for the parameter with respect to the first lens. 26.A method for achieving an effect similar to that of moving a lens in acamera while also changing a parameter associated with a lens, themethod comprising moving a first lens out of a first position in anoptical path of the camera and moving a second lens into a secondposition of the optical path of the camera, wherein the second lens issubstantially different with respect to the first lens and wherein thefirst and second positions are different from one another.